In recent years, tumor has become a type of disease severely endangering people's life, its treatment has become a subject to which numerous scientific researchers are dedicated. In addition to treatment methods such as chemotherapy, surgical resection, and the like that are commonly known to people, there has been a growing attention on tumor vaccine as a novel treatment method.
The tumor vaccine can achieve the purpose of eliminating or controlling the tumors mainly through activating patients' immune system, that is, utilizing tumor cells or tumor antigen to induce cell specific immuneresponse and humoral immune response of body, so as to enhance anti-cancer ability of the body and prevent growth, spread and recurrence of the tumors. The tumor vaccine can be divided into tumor cell vaccine, gene vaccine, polypeptide vaccine and others according to its source. The tumor cell vaccine is obtained from tumor tissues of the patients, and the inactivated tumor cells lose tumorigenicity but still keep immunogenicity, and then can be used to immunize the body; the immune mechanisms of gene vaccine mainly are through inserting tumor antigen genes into DNA expression vectors (generally are virus DNA), injecting the recombinant vectors into the bodies and expressing tumor antigen proteins to immunize the bodies; and the polypeptide vaccine are prepared through a chemical synthesis technology according to amino acid sequences of certain known or predicted antigen epitopes in the pathogenic antigen genes and then injected the polypeptide vaccine into the bodies for immunization.
However, most of the above vaccines have only entered clinical trials stage but not the clinical use stage. The main problems are as follows: the technology of transferring DNA into specific cells for expression is immature, and the safety problem of using exogenous DNA has not been solved; as the tumor cells show a high heterogeneity, that is, a plurality of tumor cells belong to the same type of tumors can express different antigens, thus T cells that activated by one tumor antigen (such as an antigen used by the polypeptide vaccine) can only kill part of the tumor cells, but not the tumor cells expressing other kinds of tumor antigens; and although the tumor cell vaccine can contain almost all kinds of the tumor antigens, the current study shows that tumor cell vaccine cannot effectively activate specific T cells and using tumor cell vaccine as vaccine is not ideal.
Therefore, how to provide a tumor vaccine which has no safety issues and can be effective to almost all the tumor antigens has becomes a problem to be solved urgently.